Electronics play an ever more important role in vehicles. Many vehicle functions are continually monitored and/or controlled by controllers. Controllers are electronic modules that are used not only to control electronic components in vehicles, but also to control machines, facilities, and other technical processes. Such controllers are embedded systems. Continually increasing requirements, for example on driving safety, reducing emissions, and reducing fuel consumption, require an increasing exchange of information among the individual controllers in vehicles.
Conventional wiring requires one line for each connection between two controllers. Thus, as the functional scope of vehicle electronics increases, the length and weight of the wiring harness and the number of connections to the controllers increases. Therefore, in modern vehicles, controllers are connected together through various system busses such as, for example, the CAN (Controller Area Network) bus, the LIN (Local Interconnect Network) bus, or the MOST (Media Oriented Systems Transport) bus. The devices use these system busses to exchange information about operating states, control commands, and other relevant data of the vehicle. In addition, such busses can be used, for example, to connect a vehicle diagnosis system.
The components used in modern vehicles place different requirements on the bus system that is used. For example, use in the area of engine management requires rapid data transmission. On the other hand, an air conditioner does not have to react to temperature changes in the passenger compartment within fractions of a second. Here, longer delays can be accepted.
Usually, various different rapid bus systems are used in a vehicle. The drive bus, e.g., the Powertrain CAN bus, includes engine, transmission, and brake controllers, as well as other sensors/actuators that are directly related with them. The Powertrain CAN bus is a high-speed CAN. A comfort CAN or body CAN is used to run comfort systems such as power windows, seat memory, or tire pressure. Simple applications such as an air conditioner or wiper control commonly use a single wire bus such as the LIN bus. The infotainment area uses MOST busses with optical waveguides because of the large quantity of data.
One or more central controllers (gateways) bring information together and are adapted to the respective bus system. The data is also forwarded from one CAN system to another. These gateways often can also be queried for diagnostic purposes.
In the long term, legislation is pushing to have diagnosis of the controllers done over Ethernet. This will result in at least one controller in a vehicle having an Ethernet connection. Ethernet is a common bus system used to access web pages. The standard protocol that networks use to transport web pages is HTTP (hypertext transport protocol).
Therefore, it is relatively simple for a controller that has an Ethernet connection to make available a web page that can be accessed by HTTP over Ethernet. Web pages are a simple way of exchanging information and are relatively popular, e.g., on the World Wide Web or Internet.
However, most vehicle controllers do not have an Ethernet connection, but rather are only connected with a CAN bus, for example. It would be desirable for controllers that do not have an Ethernet connection also be able to make web pages available to make it easier to exchange information, e.g., for diagnostic purposes or to configure the controllers.